The objective is the elucidation of the conformation of neurohypophyseal hormones, of hypophysiotrophic factors (or hormones) derived from neurohypophyseal hormones, of neurophysin proteins and of neurohypophyseal hormone-neurophysin complexes in solution and in the crystalline state and the correlation of this information with the biology of (a) the hormones--including their role in affecting membrane permeability, membrane turnover, ion transport, contractile processes and their possible role as "prohormones" for releasing and release-inhibiting factors that act at the suprahypothalamic levels in the central nervous system to alter behavior and memory; and (b) of neurophysin, including their function as binding proteins for neurohypophyseal hormones as "hormonal" signals, and their role during the biosynthesis of these hormones.